The present invention relates to a door hinge for use in installing, for example, a conventional building door or a fireproof-door or an emergency door in a fireproof-shutter, especially being capable of automatically closing the door and controlling the closing speed.
There are basically two types of known hinges. The first one, for-example such as the common door hinges, allows a door to swivel around a hinge-shaft without any auto-close function. The second one, for example such as the one discussed in Japanese Patent Appln. No, Sho 64-309942, has an auto-close function provided by a simple spring means. However, the former is disadvantageous in that in order to provide a door to be installed with an auto-close function an expensive and bulk door-closer should be additionally mounted door. The latter has the problem of impact noise whenever the door closes. Also the door may injure passers-by due to its uncontrolled closing speed.